Insects and other arthropods constitute over half of the living animal species on earth; they are important not only from a biological viewpoint but also as disease vectors and as agricultural, forest, and household pests. Insects interact chemically with one another, with plants, with hosts, and with predators. This project is concerned with elucidating these chemical interactions, which can influence both behavior and development. Among the arthropods to be studied are millipeds, centipedes, opilionids, ants, beetles and lepidoptera. Some specific objectives include the characterization of: (1) sex attractants and other pheromones of lepidoptera and of ponerine ants, and (2) defensive compounds of a wide variety of arthropods, including the lucibufagins from fireflies. We plan to carry out syntheses of any new compounds encountered and to subject these compounds to screening for antibacterial, antifungal, antiviral, antihelminthic and antitumor activity. The overall objectives of this work are: (1) to increase our understanding of natural regulatory mechanisms well enough to provide the basis for novel control techniques for disease vectors and other arthropod pests and (2) to discover new natural products which may be useful in combatting disease.